"We feel we have enough scale to run the mixed fleet efficiently," he says at the Boyd International Aviation Forecast Summit in Las Vegas today.

Seattle-based Alaska operated an all-737 mainline fleet from 2008 to 2016 when it acquired all-A320 family operator Virgin America.

Since the acquisition, Alaska executives have said that the airline will continue to operate the Virgin America fleet through the end of the aircraft leases, the majority of which expire between 2022 and 2024.

"We're going to be dual fleet for some period of time," says Tilden, adding that no decision has been made on whether to return to a single fleet type or maintain a mixed fleet.

Alaska will meet with representatives of both Airbus and Boeing over the next year or so to discuss its fleet once the Virgin America leases begin to expire, he says.

The airline remains a "proud" Boeing operator, says Tilden, even though it can no longer claim to be "all Boeing".

Alaska and Virgin America operated 65 A320 family and 156 737 family aircraft at the end of June, its latest fleet plan shows. Its regional partners Horizon Air and SkyWest Airlines operated 52 Bombardier Q400s and 26 Embraer 175s.